Coal burning magazine space heater



COAL BURNING MAGAZINE SPACE HEATER Filed Sept. 16, 1948 3 Sheets-Sheet la MA) on iM Jan. 26, 1954 DE WlTT H. WYATT COAL BURNING MAGAZINE SPACEHEATER 3 Sheets-Sheet 2 Filed Sept. 16, 1948 gwuonfotz DE W177 H W547?arty/v.05

Jan. 26, 1954 DE wrr-r H. WYATT COAL BURNING MAGAZINE SPACE HEATER 3Sheets-Sheet 3 Filed Sept. 16, 1948 HG. f.

Patented Jan. 26, 1954 UNITED STATES PATENT OFFICE 2,667,158 COALBURNING MAGAZINE SPACEHEATER De Witt H, Wyatt, Columbus, OhioApplication September 16, 1948, Serial No. 49,607

2 Claims. 1

This invention relates tospace heaters and, more particularly, toheaters or stoves of the solid fuel burning type, having specialreference to room or residence heatersor stoves employin verticalmagazine in which coal, or other solid fuels, is introduced and fedgravitationally to combustion grates or zones disposed in the lowerportions of such heaters.

It is an object of the invention to provide a coal-burning space heaterwith improved means for supplying combustion air under regulable iiow tothe grate structure and fuel combustion zone of the heater, whereby tovar automatically and control the rate-offuel combustion in accordancewith fluctuations in room temperature adjacentto the heater.

Another object of the invention is to provide a space heater of themagazine type in which the hot gases of combustion, following'theirgeneration and release from'burning fuel, are caused to flow in intimatecontact and heat-exchanging relationship with the heat-conducting wallsof a multiplicity of vertically extending channels provided in aradiator disposed within and spaced from an outer casing of the heater,room air being introduced into the bottom of the casing and directed,While traveling upwardly, over the outer surfaces of the radiator,whereby the room air is heated and discharged through outlets providedin the top .of the heater casing.

Other objects are to provide a magazine type heater utilizing solidfuels which is efficient and economical inoperation; one which requiresinfrequent manual servicing in introducing fuel or removing ash; aheater which does not produce smoke when in operation in the room inwhich it is positioned; a heater of thecharacter set forth in whichautomatic draft controls are provided responsive to floor temperaturesfor regulating the admittance of primary air into the combustion zone ofthe heater in volumes proportioned to the temperature of the airadpacent to the floor or other base surface on which the heater :ispositioned, said controls, further, being responsive to the temperaturof gases passing to the chimney r stack outlet of the heater, whereby tovary th rate of fuel combustion in a manner proportionate to thetemperature of the outletgases, and in the provision of a heatergenerally which may be economically manufactured and sold and which, inuse, is

characterized by its freedom from mechanical disorders andthesmallamcunt of manual care- 2 required in maintaining the same inactive operation.

This application constitutes a continuationin-part of my priorapplication, Serial No. 628,443 filed November 14, 1945, now Pat. No.2,545,680, ranted March 20, 1951.

For a further understanding of the invention, reference is to be had tothe following description and the accompanying drawings, wherein:

Fig. 1 is a vertical longitudinal sectional view taken through theheater;

Fig. 2 is a similar view on the plane indicated by the line 22 of Fig.1;

Fig. 3 is a horizontal sectional view on the plane indicated by the line33 of Fig. 1

Fig. 4 is a detail vertical sectional view on the line 4-4 of Fig. 1;

Fig. 5 is a diagrammatic view disclosing the automatic damper and valvecontrols governing the paths of air and gas flow through the heater.

In the specific embodiment of my invention selected for illustration inthe accompanying drawings, my improved heater comprises a substantiallycubical outer casing l. The casing includes a base structure 2 havingunited angle members 3 and a horizontally disposed plate v t whichdefines the bottom of an ash pit 5. The casing I includes a verticalfront wall 6, spaced side walls 7 and a rear wall 8, the rear wallhaving formed therewith a rearwardly projecting draft casing 9, thelatter, as shown particularly in Figs. 1 and 3, being of reduced widthas compared with that of the casing I. The upper part of the casingsupports a hingedl movable top 10, at the sidesof whichare providedstationary grills H for the escape of heated air.

In connection with this outer casing, which is composed mainly of sheetmetal plates or members rigidly maintained in their required relativeorder, the heater embodies an inner casing structure I2, the Walls ofthe latter being spaced from those of the outer casing to provide spacesS for the travel of air upwardly from the base of the heater to theoutlets provided in the grills l 3. During such upward ftravelthetemperature of the air 'israised by contact with heated surfaces oftheinner casing structure in a manner to be more fully explainedhereinafter.

Conveniently, the inner casing structure may be formed to providevertical ash pit defining Wall members 13 which, at their lower edges,are secured to the base structure 2. As shown in Fig. 2, themembers 13disposed at the sides of the ash pit 5 term ateat their upper .ends'ininwardly andhorizontally directed flanges Ill. and

downwardly and vertically directed flange l5. Positioned on and securedto the flanges I4 is the metal outer lining 16 of a ceramic fire bowll1, and in the opening provided in the bottom of this fire bowl, thereis positioned an oscillatory grate l8.

Secured to the upper portion of the vertical side members 13 aresubstantially rectangularly disposed heat-radiating plates l9. Each ofthese plates, advantageously, may be formed with substantially V-shapedheat-radiating fins 20, which project into the air circulating spaces Sto provide greater surface area for contact of the air undergoingheating with the heat-liberating surfaces of the inner casing structure.At their longitudinal ends, as in Fig. 5, the plates [9 includeadjoining radially extending flanges 2| which are engaged with verticalstay rods 22 and with which the rounded outer ends of the flanges 2! areheld in clamping engagement by means of the threaded fastening elements23, the upper and lower ends of the rods 22 being secured to bars 24rigidly attached to flanges provided at the upper and lower flangededges of the walls of the outer casing.

By reference to Fig. 2, it will be noted that the side and back walls 1and 8 of the outer casing at their lower edges terminate in a horizontalplane above that of the base structure 2, so that air may be drawn fromthe floor level and advanced upwardly through the spaces S for heatingcontact with the walls of the inner casing structure. The base structurealong the sides and. back thereof is formed to provide channels 25, andin these channels, there are seated ceramic water Vaporizers 26.

Below the grate iii, the ash pit receives a removable ash pan 21. Thefront wall of the outer casing, in registration with the ash pit, isprovided with an opening for the reception of a removable panel 28, bywhich access is provided to the ash pit for the purpose of removing orinserting the ash pan. The panel may be formed with inwardly facinggaskets 29 to seal the edges of the opening therefor when the panel isoperatively positioned, as shown in Fig. 3.

The plates I9, adjacent to the upper edges of the fire bowl ll areshaped to provide grooves 30. In these grooves, metallic frame bars 3|are seated, the bars resting on the upper of the ceramic bowl [1 and itsouter lining. Positioned on bars 3! are the lower and outer surfaces ofa plurality of substantially rectangular duct-forming blocks 32 ofceramic composition, these blocks having their inner and side surfacesformed with ribs and grooves 33 which interfit where adjacent blocksmeet, as in Fig. 5.

By reference to Figs. 1 and 2, it will be noted that the lower surfacesof these refractory blocks overhang the fire bowl area, and since eachblock is formed to include a plurality of vertically extendingcombustion gas passages 34 and combustion air-supplying passages 35, the

lower ends of these passages will be disposed in open communication withthe fire bowl, the latter forming the fuel combustion zone of theheater. It will be noted. that the blocks 32 are so arranged as toconstitute a vertical fuel magazine with fuel storage capacity. Solidfuels are introduced into the top of this magazine and are fedgravitationally in a downward direction therethrough into the fire bowlwith the burning fuel supported on the grate l8. The outer walls of thisgrate are spaced as at 36 from the adjacent inner walls of the fire bowll1, so that surfaces primary air for fuel combustion purposes may bedrawn from the ash pit, in a manner hereinafter described, and suppliedto the burning fuel.

Also, as hereinafter defined, secondary air for fuel combustion purposespasses downwardly through the ducts of the blocks 32 and is combinedwith the burning fuel to sustain active combustion thereof. Under thenormal draft of the heater, these burning gases pass upwardly throughthe combustion passages 34, heating the walls of the passages and, inturn, the adjoining heat-radiating plates 19 and their fins 20, so thatthe heat generated by the burning fuel will be transmitted to the roomair passing upwardly through the spaces S.

The grate structure It, in this instance, has been shown ascomprising ametallic casting 31 which contains and supports a body 38 of a ceramicrefractory, the body being formed with reversely inclined upper surfaces39, which are adapted to direct ash toward the sides of the grate, sothat when the latter is rocked, fine ash may be deposited in the pan 2?.At its front and rear ends, the casting 31 is formed with trunnionsrockably supported in bearings 41 carried by the inner casing structure.The front trunnion 40 may have its outer end engaged with the slottedlower end of a link 42 which, at its upper end, is pivotally attached asat 43 to a grate-rocking handle 44. Normally, and as shown in Fig. 3,this handle occupies a downwardly inclined position to the rearof aremovable panel 45 positioned in an opening formed in the front Wall ofthe outer casing I above the ash pit panel 28. When the panel 45 isremoved, the handle 44 may be swung upwardly to an operating position.

When in a substantially horizontal position, the bifurcated end 46 ofthe handle will be removed from engagement with a stationary stop lug4'! formed with the metallic lining of the fire bowl, thus permittingthe handle to be manually actuated to rock the grate on its trunnions 40and thereby remove ash from the combustion zone. It will be noted thatwhen the handle 44 occupies its lower position, the engagement of thebifurcated end 45 thereof with the lug 41 will retain positively thegrate against rocking movement.

The upper portions of the plates l9, adjacent the plane of the upperedges of the blocks 32, are recessed to receive the shouldered andoffset lower edges 48 of a plenum ring 49. This ring defines a plenumchamber 58 for receiving the gaseous products of combustion issuing fromthe upper ends of the ducts 34. The chamber 50 is spaced from the fuelmagazine M by a plurality of spaced inwardly disposed divisional plates5| and 52, the lower edges of the latter resting on upper edge surfacesof the blocks 32, while the upper edges of the plates 5i and 52 engagewith inwardly and downwardly directed flanges 53 formed with the plenumring 49. The flanges 53, as shown in Figs. 1 and 2, terminate in adownwardly directed spout 54 having downwardly and inwardly inclinedwalls, and by means of which spout, fuels are directed into the upperpart of the magazine M. By reason of the inclination of the walls of thespout and the extent to which they project into the top of the magazine,suincient spacing exists between said spout and the walls 52 to form asmoke trap T.

The top It comprises a hollow sheet metal structure, having afinger-gripping recess 55 formed in the front thereof. At its rear, thetop is provided'witha'hinge pintle 5B which is received in bearingsformed withthe top of the plenum ring 49,- so that by gripping the topwith the aid of the recess 55, the same may be raised and lowered, byswinging movement in a vertical plane. The bottom of the top is providedwith a lid 51 which seats on a shoulder 58 provided by the walls of thespout 54, so that when the top is lowered, the openable upper end of themagazine will be closed thereby. The lid 57 is connected with the top bymeans of the fastening screws and nuts shown at 59.

As shown more particularly in Figs. 4 and primary air for fuelcombustion purposes enters the lower part of the draft casing 9 by wayof an opening 60 in one of the walls thereof. The amount of air passingthrough this opening is controlled by means of a weight-balanced dampervalve 6i suspended from a fixed pivot 62. When the valve Si is open, asin Fig. 4, atmospheric air passes into the lower portion of the draftcasing 9 and passes over a baille Wall 63 disposed at the rear of theash pit 5. By the provision of the walls shown at 64 and 65, a primaryair chamber 66 is formed in the bottom of the draft casing 9. The walls63 and 65 are spaced so that primary air flows from the chamber 66 intothe ash pit and thence upwardly around the grate structure into the fuelbed present in the fire bowl I1.

Supported below the bottom wall of the primary air chamber in a positionto be responsive to floor temperatures exteriorly of the heater is abellows-type thermostatic element 61, which expands and contracts in theusual manner in response to temperature variations. The element 6!includes an upstanding rod 68, which engages with a bearing socketprovided in one end of a lever arm 69. This arm intermediately of itslength is connected with a pivot shaft Hi which, as shown in Fig. 4, isrotatably supported at its ends in bearings H carried by the side Wallsof the chamber 66. Adjacent to one of its ends, the shaft 10 carries acrank lever 72 which engages with an offset flange 13 formed with thedamper valve Bl, so that as the rock shaft l8 oscillates, in response tothe action of the thermostatic element 61, the damper valve 6| will bemoved to positions opening or closing the primary air inlet 60. When theair temperature surrounding the thermostatic element 67 is below apredetermined value, the pivot shaft 10 and its crank lever 12 assumepositions providing for the automatic opening of the damper valve e: andthe flow of combustion air into the heater under the draft flow of theheater. When the room temperature ambient to the thermostatic elementexceeds the predetermined value, the element expands to move the valve61 toward or into a position obstructing the inflow of air into theheater through the opening 60.

Arranged within the draft casing 9 above the walls 64 and 55 is aninclined bafiie 14 which forms a check air receiving chamber 15, thebaifle 7d being formed with an opening- 16 providing for the flow ofairfrom the chamber into a flue chamber 11 provided in the upper portionsof the casing 9, the flue chamber being in open communication with theplenum chamber 50 at the rear of the heater. The top of the flue chamber1! is formed with a waste gas outlet 18, leading to an associated outletflue or chimney, not shown. The gaseous products of combustion, aftertraveling through the combustion passages 34 of the blocks 32, enter theplenum chamber and thence travel into the flue chamber 11, leaving theheater by Way of the waste gas outlet 18.

As the waste gases travel through the flue chamber, and before enteringthe outlet 18, the same pass over a thermostatic element 19. Thiselement includes a manual control in the form of the externallypositioned knob, indicated at 86, so that the element 19 may be adjustedfor obtaining heater response to different operating temperatures. Themovable part of the element '9 includes a depending rod 8| which, at itslower end, has a pivotal connection with one end of the lever arm 69opposite to that with which the rod 68 is associated. By the adjustmentof the knob 80, the draft controls of the heater may be manuallyregulated to maintain substantially uniform any desired temperaturewithin the working range of the heater. The thermostat I9 is of thebellows type, specifically disclosed in my aforesaid prior copendingapplication, involving an expanding bellows element. The floorthermostat 61 is also of the bellows type, the two thermostats, 61 andE9, operating conjointly in response to temperature conditionsprevailing adjacent the floor of the heater and in the flue chamber 71to regulate the operation of the various Valves of the heater, shown at6!, 84, 90 and 96', in obtaining a regulated delivery of heat inresponse to changing room temperatures. 7 7

Thus, if the temperature of the gases passing over the thermostaticelement 79 should exceed a predetermined value, said element responds todepress the rod 8|, which rocks the lever arm E9 and the pivot shaft 10in adirect causing the crank lever 12 to elevate a rod 82 connectedtherewith. This rod is engaged with an ofiset flange or lip 83 providedon a pivot check airregulating valve 84. This valve 'normally closes anopening 85 provided one of the side walls of the chamber 15. Theelevation of the rod 82 rocks the check air valve about its pivot 85,thereby permitting air to be drawn from the atmosphere into the chamber15 and thence into the flue chamber 11.

At the same time, the oscillation of the lever arm closes orpartiallycloses the opening 65 through the associated operation of thedamper valve 6|, causing a lower rate of fuel combustion in the firebowl of the heater. If desired, the lever arm 69 may have the weightthereon counter-balanced by a coil spring 87, so that it soperationtakes place freely and easily and in ready response to the controlsprovided by the thermostatic elements 6? and I9 and their respectiveparts.

Secondary combustion air isadmitted into the chamber 38 formed betweenthe walls 5! and 52 by means of an air inlet '89 provided in the top ofthe plenum ring 49. This inlet is opened and closed by a valve shutter9-9 which turns about a pivotal mounting Si. in order to provide forautomatic control over the operating positions of the shutter 90, thereis connected with its pivotal mounting a depending crank arm 92'. Thelower end of this crank arm, as shown in Fig. 5, is pivotally joined atone end of a link 93, the other end of said link beingpivotallyconnected with the longer arm of a b'ell'cranl-z lever 95. Theshorter arm of this lever in confined between spool-forming collars 55on the rod 81 of the thermostatic elements 19, so that the valve shutterSiiwill assume open or closed positions with respect to the air inlet'89 in "accordance with the opening and closingof the primary air-valve6|.

To prevent the escape of smoke from the upper portion of the fuelmagazine and its release into the room atmosphere, particularly underconditions where a fire is being freshly started in the heater and whilethe outlet fiue or chimney may be at a low temperature and not properlywarmed, I provide a by-pass valve 96 which is pivotally mounted as at 91to open or close an opening 98 formed in the wall 52 adjacent to the topof the fuel magazine. Normally, the by-pass valve 96 is closed but underconditions which produce the presence of smoke in the upper part of thefuel magazine, the lever 94 is rocked so that a link 99 connected withthe longer arm of said lever is moved to assume a position opening theby-pass valve and providing for the convenient escape of smoke into theplenum chamber and thence to the waste gas outlet of the heater. Whennormal draft conditions obtain with accompanying fuel combustion ratesand draft pull through the heater, the by-pass valve is closed.

Consideration of these features of construction and operation will makeit clear that the present invention provides a coal-burning room orspace heater which may be maintained in operation over relativelyprolonged periods of time without requiring manual attention. The usualcoalburning heater of thi category requires frequent manual attention inthe matter of replenishing the coal supply and in adjusting draftcontrols to secure desired rates of fuel combustion and roomtemperatures.

In the present heater, the magazine M, after a fire has been initiatedin the combustion bowl, may be filled to the limit of its storagecapacity. As the fuel is consumed, through combustion, the samegradually settles in the hopper toward the fire bowl, maintaining in thelatter at all times a proper amount of fuel for combustion-sustainingpurposes. As the coal or other fuel thus settles, its temperature isgradually increased. The freely removable volatiles contained thereinare first distilled off in the form of gases 01' vapors, and under draftpull of the furnace pass along the grooved surfaces 33 of the blocks 32and, upon ignition, enter the combustion passages 34, burning activelyin these passages.

The solid fuel in the combustion zone, provided by the fire bowl, issubstantially in the form of coke and burns freely with a minimum ofcoarse ash or clinker formation. The walls of the blocks 32 becomehighly heated by fuel combustion taking place in the passages 34, andthis heat is transmitted by conduction, convection and radiation to theair drawn from the floor of the room and passing upwardly through thespaces S around the heat radiating plates 19, their fins and the wallsof the plenum ring 49.

If desired, the hollow fins 20 may be filled, as indicated at I09, witha heat-conducting material. Usually thermal circulation of the airundergoing heating is all that is required in the average installation,although it is within the scope of the invention to employ conventionalforced circulation of the air if such should be desired. It will also benoted that air for combustion regulating and modifying purposes isintroduced into the heater at three different levels.

First: the primary air for fuel combustion purposes enters the heaterfrom about the fioor level thereof, as provided by the opening second,the check fuel combustion air enters the casing by way of the opening85, which is disposed at a higher level in the flue casing than theprimary air opening, and, third, secondary air for fuel combustionpurposes enters the casing through the air inlet 89 at the top thereof.By locating the thermostatic control element 61 adjacent the floorlevel, the operation of the heater is rendered more satisfactory to roomoccupants. Under normal draft pull, smoke or volatile fuel particlescontained in the bowl of the magazine is drawn downwardly and preventedfrom passing in an upward direction. It is only when abnormal draftconditions are present that the by-pass valve 96 need be opened.

It will be noted that the air undergoing heating, passes upwardlythroughout substantially the complete height of the heater, thus havingample opportunity to contact the heat-releasing surfaces thereof toprovide for efiicient heat interchange. Through the operation of theautomatic draft controls, the heater will maintain uniform roomtemperatures which are in marked contrast with the highly fluctuatingtemperatures provided by ordinary heaters having manually regulateddraft controls. The mechanical structure of my improved heater isessentially simple and readily assembled, so that the same may beeconomically manufactured and sold. Materials have been selected, suchas the employment of the refractories provided in the construction ofthe grate 18, the fire bowl I! and the blocks 32 which highly resistdeterioration from high temperatures. Otherwise, sheet metal is largelyused in the construction of the heater for reasons of manufacturingeconomy. Over the opening it in the baflle M, a shield 0| may be placedto prevent light ash contained in the flue gases from depositing in thechecking air chamber. The removable panel doors are provided in thefront opening of the ash pit and the grate shaker for the purpose ofnormally closing the front of the outer casing and enhance itsappearance. Similarly, the lid for the fuel inlet of the magazine ispivotally mounted on the swinging top, adding symmetry to the externallines of the outer casing. Adjacent to the primary air inlet, the draftcasing 9 may be provided with an access door I92 so that convenience maybe had in adjusting the thermostatic controls present in the primary airchamber. Usually these adjustments are factory or service mensadjustments and ordinarily it is only necessary for the user of theheater to provide desired temperature ranges through adjustments of theknob 90 of the thermostatic element l9.

Iclaim:

1. In a coal-burning heater, a main casing structure formed internallyto provide in vertical superposed order an ash pit, a grate, a fire bowland a fuel magazine; said magazine having a refractory lining formedwith a plurality of open-ended passages for the transmission of burningand heated combustion gases and with a plurality of open-ended adjacentpassages for the transmission of combustion air to said fire bowl;spaced inner and outer divisional plates mounted on said refractorylining and defining between them an air chamber in the top of saidheater which is'in open communication with the passages of said liningemployed for the transmission of combustion air; said chamber having anair inlet, a valve member for said air inlet which when open providesfor the passage of air from the atmosphere downwardly through said airchamber and. through the air-conducting passages of the refractorylining to the fuel contained in said fire bowl; a plenum chamber havinga flue outlet formed in the top of said heater casing around the outerof said divisional plates, said plenum chamber being in communicationwith the open upper ends of the flame and combustion gas passages ofsaid lining, and thermostatic means disposed in heat-exchange relationto flue gases present in said plenum chamber and responsive topredetermined increase or decrease in the temperature of said gases fordecreasing or increasing the quantity of air admitted by said valvemember into said air chamber.

2. In a coal-burning heater, a main casing structure formed internallyto provide in vertical superposed order an ash pit, a grate, a fire bowland a fuel magazine; said magazine having a refractory lining formedwith a plurality of open-ended passages for the transmission of burningand heated combustion gases and with a plurality of open-ended adjacentpassages for the transmission of combustion air to said fire bowl;spaced inner and outer divisional plates mounted on said refractorylining and defining between them an air chamber in the top of saidheater which is in open communication with the upper ends of thecombustion air passages of the lining; said chamber having an air inlet,a valve member for said air inlet which when open provides for thepassage of air from the atmosphere downwardly through said air chamberand through the air-conducting passages of the refractory lining to thefuel contained in said fire bowl; a plenum chamber having a flue outletformed in the top of said heater casing around the outer of saiddivisional plates, said plenum chamber being in communication with theopen upper ends of the flame and combustion gas passages of said lining;thermostatically operated means responsive to the temperature of gasespresent in said plenum chamber and the outlet thereof for operating saidair inlet valve member to increase or decrease the amount of combustionair entering the air chamber and delivered by said combustion airpassages to the fire bowl; means forming a smoke outlet leading fromsaid inner divisional plate to said plenum chamber, a second movablevalve member for closing said smoke outlet, and link devices actuated bysaid thermostatic means for operating the valve member of said smokeoutlet.

DE WI'IT H. WYATT.

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